pyenvを用いてCentOSにPythonをインストール

# 0. 環境
CentOS6.7

# 1. 必要そうなものをインストール

```bash
$ sudo yum groupinstall "Development tools"
$ sudo yum install gcc zlib-devel bzip2-devel openssl-devel readline-devel ncurses-devel sqlite-devel gdbm-devel db4-devel expat-devel libpcap-devel xz-devel pcre-devel
```

# 2. pyenvをインストール 
```bash
$ git clone https://github.com/yyuu/pyenv.git ~/.pyenv
$ echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bash_profile
$ echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bash_profile
$ echo 'eval "$(pyenv init -)"' >> ~/.bash_profile
$ exec $SHELL

```

## 2.1 実行してみる。

```bash
$ pyenv
pyenv 20151006-3-g1550129
Usage: pyenv <command> [<args>]

Some useful pyenv commands are:
   commands    List all available pyenv commands
   local       Set or show the local application-specific Python version
   global      Set or show the global Python version
   shell       Set or show the shell-specific Python version
   install     Install a Python version using python-build
   uninstall   Uninstall a specific Python version
   rehash      Rehash pyenv shims (run this after installing executables)
   version     Show the current Python version and its origin
   versions    List all Python versions available to pyenv
   which       Display the full path to an executable
   whence      List all Python versions that contain the given executable

See `pyenv help <command>' for information on a specific command.
For full documentation, see: https://github.com/yyuu/pyenv#readme
```

走った。

## 2.2 インストールできるバージョンを確認。

```bash
$ pyenv install --list
Available versions:
  2.1.3
  2.2.3
  2.3.7
  2.4
  2.4.1
  2.4.2
  2.4.3
  2.4.4
  2.4.5
  2.4.6
  2.5
  2.5.1
  2.5.2
  2.5.3
  2.5.4
  2.5.5
  2.5.6
  2.6.6
  2.6.7
  2.6.8
  2.6.9
  2.7-dev
  2.7
  2.7.1
  2.7.2
  2.7.3
  2.7.4
  2.7.5
  2.7.6
  2.7.7
  2.7.8
  2.7.9
  2.7.10
  3.0.1
  3.1
  3.1.1
  3.1.2
  3.1.3
  3.1.4
  3.1.5
  3.2-dev
  3.2
  3.2.1
  3.2.2
  3.2.3
  3.2.4
  3.2.5
  3.2.6
  3.3.0
  3.3-dev
  3.3.1
  3.3.2
  3.3.3
  3.3.4
  3.3.5
  3.3.6
  3.4.0
  3.4-dev
  3.4.1
  3.4.2
  3.4.3
  3.5.0
  3.5-dev
  3.6-dev
  anaconda-1.4.0
  anaconda-1.5.0
  anaconda-1.5.1
  anaconda-1.6.0
  anaconda-1.6.1
  anaconda-1.7.0
  anaconda-1.8.0
  anaconda-1.9.0
  anaconda-1.9.1
  anaconda-1.9.2
  anaconda-2.0.0
  anaconda-2.0.1
  anaconda-2.1.0
  anaconda-2.2.0
  anaconda-2.3.0
  anaconda3-2.0.0
  anaconda3-2.0.1
  anaconda3-2.1.0
  anaconda3-2.2.0
  anaconda3-2.3.0
  ironpython-dev
  ironpython-2.7.4
  ironpython-2.7.5
  jython-dev
  jython-2.5.0
  jython-2.5-dev
  jython-2.5.1
  jython-2.5.2
  jython-2.5.3
  jython-2.5.4-rc1
  jython-2.7.0
  jython-2.7.1b1
  jython-2.7.1b2
  miniconda-2.2.2
  miniconda-3.0.0
  miniconda-3.0.4
  miniconda-3.0.5
  miniconda-3.3.0
  miniconda-3.4.2
  miniconda-3.7.0
  miniconda-3.8.3
  miniconda-3.9.1
  miniconda-3.10.1
  miniconda-3.16.0
  miniconda3-2.2.2
  miniconda3-3.0.0
  miniconda3-3.0.4
  miniconda3-3.0.5
  miniconda3-3.3.0
  miniconda3-3.4.2
  miniconda3-3.7.0
  miniconda3-3.8.3
  miniconda3-3.9.1
  miniconda3-3.10.1
  miniconda3-3.16.0
  pypy-c-jit-latest
  pypy-c-nojit-latest
  pypy-dev
  pypy-stm-2.3
  pypy-portable-2.3.1
  pypy-portable-2.4
  pypy-portable-2.5
  pypy-portable-2.5.1
  pypy-stm-2.5.1
  pypy-portable-2.6.0
  pypy-portable-2.6.1
  pypy-1.5-src
  pypy-1.5
  pypy-1.6
  pypy-1.7-dev
  pypy-1.7
  pypy-1.8-dev
  pypy-1.8
  pypy-1.9-dev
  pypy-1.9
  pypy-2.0-dev
  pypy-2.0-src
  pypy-2.0
  pypy-2.0.1-src
  pypy-2.0.1
  pypy-2.0.2-src
  pypy-2.0.2
  pypy-2.1-src
  pypy-2.1
  pypy-2.2-src
  pypy-2.2
  pypy-2.2.1-src
  pypy-2.2.1
  pypy-2.3-src
  pypy-2.3
  pypy-2.3.1-src
  pypy-2.3.1
  pypy-2.4.0-src
  pypy-2.4.0
  pypy-2.4-beta1-src
  pypy-2.4-beta1
  pypy-2.5.0-src
  pypy-2.5.0
  pypy-2.5.1-src
  pypy-2.5.1
  pypy-2.6.0-src
  pypy-2.6.0
  pypy-2.6.1-src
  pypy-2.6.1
  pypy3-dev
  pypy3-portable-2.3.1
  pypy3-portable-2.4
  pypy3-2.3.1-src
  pypy3-2.3.1
  pypy3-2.4.0-src
  pypy3-2.4.0
  stackless-dev
  stackless-2.7-dev
  stackless-2.7.2
  stackless-2.7.3
  stackless-2.7.4
  stackless-2.7.5
  stackless-2.7.6
  stackless-2.7.7
  stackless-2.7.8
  stackless-3.2-dev
  stackless-3.2.2
  stackless-3.2.5
  stackless-3.3-dev
  stackless-3.3.5
  stackless-3.4.1
```

## 2.3 "2.7.10"と"3.5.0"をインストールする。

```bash
$ pyenv install 2.7.10
Downloading Python-2.7.10.tgz...
-> https://yyuu.github.io/pythons/eda8ce6eec03e74991abb5384170e7c65fcd7522e409b8e83d7e6372add0f12a
Installing Python-2.7.10...
patching file ./Lib/site.py
Installed Python-2.7.10 to ~/.pyenv/versions/2.7.10

$ pyenv install 3.5.0
Downloading Python-3.5.0.tgz...
-> https://yyuu.github.io/pythons/584e3d5a02692ca52fce505e68ecd77248a6f2c99adf9db144a39087336b0fe0
Installing Python-3.5.0...
Installed Python-3.5.0 to ~/.pyenv/versions/3.5.0

$ pyenv rehash
```
## 2.4 インストールされたバージョンを確認。

```bash
$ pyenv versions
* system (set by ~/.pyenv/version)
  2.7.10
  3.5.0

$ pyenv global 2.7.10
$ python
Python 2.7.10 (default, Oct 28 2015, 11:37:48) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-16)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

```

## 2.5 バージョンを切り替え
```bash

$ pyenv global 3.5.0
$ python
Python 3.5.0 (default, Oct 28 2015, 11:40:43) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

```